Incontinence is a common condition that few women discuss with their medical provider. In this grant application, we propose to capitalize on the availability of two large prospective studies of women aged 37-85 years, to examine the epidemiology of urinary incontinence (UI) across varying age groups. Although parity is an established predictor of incontinence, detailed data on reproductive characteristics are sparse, and large prospective epidemiologic studies on additional risk factors are rare; in particular, since lifestyle may change as a result of incontinence, it is essential to identify and confirm associations in prospective data so that cause and effect are not misappropriated. We plan to examine prospectively the relation of reproductive characteristics, body weight and physical activity, and hormonal factors to the incidence of UI, to different types of UI (urge, stress, or mixed incontinence), to its severity, its progression, and to its impact on women s daily lives. The investigation will utilize the Nurses Health Study and the Nurses Health Study II, observational studies of 121,701 and 116.678 female nurses, respectively. Extensive data are collected via biennial, mailed questionnaires (since 1976 for NHS and since 1989 for NHSII) regarding lifestyle and numerous diseases. This includes updated reproductive information, body weight, exercise habits, menopause, exogenous hormone use, and many other items. Details regarding incontinence will be established via a comprehensive supplementary questionnaire to all women who report leaking on the main questionnaires; this will elicit data on type of incontinence, treatment, and extent to which the incontinence is bothersome or restrictive. Based on preliminary data from NHS, the 33.8% prevalence of incontinence is similar to that reported by other groups, and the 3.2% four-year incidence rate is comparable to that in the few existing follow-up studies. These similarities indicate the nurse participants report incontinence accurately and that our data are generalizable to other populations. Both NHS and NHSII have maintained extremely high participation (over 909~ in both studies to date). These two existing cohorts provide a cost-efficient basis for conducting a prospective study of UI, allowing better understanding of the epidemiology of UI, and identification of preventive strategies. In addition, the establishment of these cohorts for studying incontinence will allow future investigations of many other issues, such as the effect of diet and various lifestyle habits.